A possible two cell pocket power house (although not hundred of lumens) is:
2xcell Vital Gear, E2C, "C" bezel, 2 rechargable CR123's, P90 lamp.
I have built such an unit and it is very small and very bright, with an estimated 20-30 minutes run time.
You could also run (or try to run) a P91 lamp in there, with the corresponding shorter runtime.
The best part is that is running on guilt-free lumens /ubbthreads/images/graemlins/grin.gif
Will